Broadly Neutralizing Antibodies in HIV Patients

Researchers identify aspects of the patient, the virus, and the infection itself that influence whether a person with HIV will produce broadly neutralizing antibodies.

Sep 28, 2016

Jef Akst

WIKIMEDIA, BRUCEBLAUSEOnly about 1 percent of HIV-infected people will generate the broadly neutralizing antibodies that target conserved spiked viral structures and can thus recognize multiple strains, and could one day serve as the basis for an effective vaccine. Now, thanks to work out of the University of Zurich and University Hospital Zurich (UZH) in Switzerland, researchers have a few clues as to who makes these broadly neutralizing antibodies and when. The team’s results were published this week (September 26) in Nature Medicine.

“Our results show how different factors boost the formation of antibodies that broadly combat different viral strains. This will pave the way for us to systematically push ahead with the development of an effective vaccine against HIV,” study coauthor Alexandra Trkola, a professor of medical virology at UZH, said in a press release.

Examining some 4,500 HIV+ participants of the Swiss HIV Cohort Study and the Zurich Primary HIV Infection Study, the researchers found that 239 of them had formed broadly neutralizing antibodies. Further analysis revealed that the viral load in the body, the diversity of viruses found in that individual, and how long the patient went without treatment were key factors in determining which patients produced these antibodies.

Interestingly, these factors independently affect broadly neutralizing antibody production, study coauthor Huldrych Günthard, a professor of clinical infectious diseases at UZH, told Medical News Today. “So we don’t necessarily have to consider all three parameters in designing an HIV vaccine. This is especially important with regard to the length of vaccine administration—it wouldn’t be possible to imitate a longer untreated HIV infection with a vaccine.”

Günthard and colleagues also found host-specific factors—including ethnicity—that influenced the probability that a patient would produce broadly neutralizing antibodies: black patients with HIV produce the antibodies more frequently, even when controlling for other factors. Genetics, geographic location, and socioeconomics could all play a role, the authors noted.

Thirdly, different virus subtypes appeared more or less likely to trigger the production of broadly neutralizing antibodies. Subtype B viruses, the researchers found, tend to elicit antibodies that bind to CD4 binding sites on the virus, while other subtypes tend to elicit antibodies that bind to V2 glycan, a sugar element of HIV’s conserved spikes.